Tensioning device for flexible members



1936. K. MICHELSON 24,

TENSIONING DEVICE FOR FLEXIBLE MEMBERS Filed April 27, 1934 Fig.1.

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a/ on Patented Aug. 18, 1936 UNITED STATES PATENT orgies TENSIONINGDEVICE FOR FLEXIBLE MEIVIBERS Konstantin Michelson, Tallinn-Reval,Esthonia Application April 27, 1934, Serial No. 722,772 I In FinlandApril 10, 1933 4 Claims.

My invention relates to tensioning devices for flexible members, such ascables, or the cords connecting telephones, flat irons, lamps, and otherelectrical appliances, to a system. Such 5 cords are subject to damageas they mostly hang downfreely on account of their length and so getkinked or looped, and finally break. The cords are also very troublesomein the manipulation of the appliances to which they are connected, asthey have a tendency to get entangled and must be disentangled beforethe appliance can be used. v

It is an object of myinvention to eliminate the diificulties involved bythe use of such cords so as to prevent breaking and entangling, andother unfavorable occurrences. To this end, in a tensioning device forflexible i members according to my invention, I provide a shaft, meanssuch as a frame in which the shaft is mounted, for supporting the shaftthrough the member which is to be tensioned, and on this i shaft Iarrange a rotary drum for winding the flexible member.

My novel device is so designedthat itcan be connected to the flexiblemember, or cord, without any alterations in the member, and withoutdisconnecting the member. The device is fitted to any cord or the likeby a few manipulations, without disconnecting one end of the cord, andso it may be. fitted, for instance, to existing telephones in which thereceiver is permanently connected to the apparatus.

In a preferred embodiment of my invention, the shaft on which the rotarydrum is mounted, is carried by a frame equipped with guiding rollers forthe flexible member and is supported on the member by means of therollers.

In the accompanying drawing, a device embodying my invention isillustrated by way of example.

In the drawing Fig. 1 is a plan view, and

Fig. 2 is an elevation of the device,

Fig. 3 is a section on the line III-III in Fig. 2,

Fig. 4 is a section on the line IV--IV in Fig. 3.

Fig. 5 is an axial section of a coiled spring by which the drum isconnected tothe shaft.

Fig. 6 is a section on the line VIVI in Fig. 2, and

Fig. '7 illustrates the arrangement of my device on a telephone.

Referring now to the drawing, and first to Figs. 1 to 3, the drumcomprises a hollow barrel 2, and a pair of side plates l at oppositeends of the barrel. The side plates l are held against the ends of thebarrel .2 by stays 9, Fi and crozes are formed in the side plates forlocating the barrel. 'The sidezplates are equipped with central bossesfor the reception of ashaft l which is held against rotation in the twomembers 5 and 5 of a frame, by screws 6. w r

The drum is insulated, or, preferably, made of insulating material, suchas compositions known by the trade names of bakelite, galalith, etc.

Housed within the barrel of the drum is a torsion spring 3 which, asbest'se'en in Fig. 5, com prises an outer portion 3a, and an innerportion 3b which is arranged co-aXially in'the'outer portion 3a.Theoverall size of the spring is reduced by the co-axial arrangement ofits portions. The two portions are wound froma singlewire but they mightalso be'separate members. a

One end of the spring' '3 is at the upper endof its co -axial innerportion3b, andis connected to the shaft 4 at 3c, Fig. 3. The other'end3d of the spring is at the upper end of its outer portion 3a, and isattached to one of the stays 9 of the drum. In this manner, the ends'ofthespr'ing are anchored to the shaftll and, through the shaft, to theframe 5,-and to the drum,- respectively, and the spring serves forrotating'the drum and for Winding the flexible member or cord ll.

Any suitable means, for instance a hook Hi0, as illustrated in Fig. 4,may be provided for securing the cord II to the drum. Preferably,however, a connection is provided which does not project outwardly fromthe barrel 2, like the hook Illa, because such a projecting member mayinterfere with the winding of the cord on the barrel. Preferably, thebarrel has a recess or depression III, as also shown in Fig. 4, and aslide Illa which is mounted in grooves lllb at the sides of the recessor depression ill, for partly closing the recess, so as to retain thecord in the recess.

The frame 5, 5' encloses the drum, as shown in Fig. 1, and has two armsat whose ends a grooved roller 6 and a plain roller 1, and a groovedroller 6 and a plain roller 1, respectively, are arranged to rotateabout stays, 8, 8a and 8', 8a, respectively. The stays are threaded sothat any one of the rollers may be removed after unscrewing its stay.One reach of the cord I I is guided by the rollers 6 and 1, and theother reach by the rollers 6' and l. The individual pairs of rollers arestaggered with respect to the central plane l2l2 of the drum, as shownin Fig. 1, in order to effect uniform winding of the individual reaches.

The frame 5, 5 is insulated or, preferably, made of insulating material,like the drum, so that short-circuiting is avoided if the insulation ofthe cord II is defective. The frame members have a somewhat complicatedconfiguration, with portions having bends or kinks. In order to make theframe members strong enough, notwithstanding their being of insulatingmaterial, strengthening ribs are provided at the sharper kinks, forinstance at l3 and [4 on the frame member 5 where a rib I5 is formed onthe outer side of the frame member, and a rib I6 on its inner side,respectively. Similar ribs are provided at corresponding points of theframe member 5, and elsewhere, as may be required. Portions which arebent less abruptly, for instance the portion which extends from the kinkM of frame member 5 to the shaft 4, may be re-inforced by insertions llof fibrous material, to prevent breaking of the frame members whendropped.

In operation, the stays 8 of the roller 6', and 8a. of the roller 1, areunscrewed, and the rollers 1 and 6 are removed. The cord II is thendoubled up to form a loop. Before this is done, the drum must obviouslybe rotated several times in order to put tension on the spring 3, inconformity with the length of the cord l I. After the cord has beenlooped, and the loop placed in the recess or depression [0, the: slideIlla is pushed forward to retain the loop which is now locked in itsposition. The drum is now released and rotated by the reaction of thespring 3a, windmg the two reaches of the cord on the drum from oppositesides. The cord II is placed on-the rollers 6 and I, and the rollers and6' are reinserted, their stays 8a and .8 being screwed into the framemember 5'. The device is now supported by the cord ll.

Fig. 7 illustrates the arrangement of my device on a telephone. Only thedrum is illustrated in Fig. 7. The cord H is attached to the casing 20of the telephone at one end, and to its receiver 2| at the other end.When the receiver 2| is raised, the cord II is unwound from the drum,and tension is put on the spring 3. When the receiver is returned intoits initial position, the spring 3 turns the drum in opposite direction,winding the cord ll uniformly on the drum. The cord is always undertension and the formation of loops, and other undesirable events, areprevented.

I claim:

1. In a tensioning device for flexible members, a shaft, means forsupporting said shaft on the member to be tensioned, a rotary drum onsaid shaft for winding the member, said drum having a recess for thereception of a portion of member, and a slide on said drum which spanssaid recess and is mounted for displacement parallel to the axis of saiddrum, for retaining the member in the recess.

2. A tensioning device for electrical conducting cords and the like,including a shaft supported by the cord, a drum adapted for winding thecord rotatable on the shaft including a hollow cylindrical body, meansfor detachably connecting the cord to the body of the drum consisting ofa longitudinally extending recess depressed in the periphery of the bodyof the drum, and an arcuate member partially closing the recess andslidably engaged with the walls thereof.

3. A tensioning device for electrical conducting cords and the like,including a shaft supported by the cord, a drum adapted for winding thecord rotatable on the shaft, means for detachably connecting the cord tothe drum, and a supporting frame associated with the drum and includinga series of bends of varying sizes, reinforcements at the bends, thereinforcements at the larger bends being in the form of strengtheningribs while the reinforcements at the smaller bends consist of fibersembedded in the material of which the frame is formed. 7

4. A tensioning device for electrical conducting cords and the likeincluding a shaft supported by the cord, a drum adapted for winding thecord rotatable on the shaft, means for detachably connecting the cord tothe drum, and a single torsion spring formed from a single piece ofmaterial and consisting of two parts in coaxial relation to each other,both parts being arranged between the drum and the shaft and also incoaxial relation therewith.

KONSTANTIN IVIICHELSON.

